The invention relates to a blade wheel for a centrifugal pump. The blade wheel has at least one row of generally radial blades successively in the circumferential direction of the blade wheel, the radially outermost blade ends being at an oblique angle .alpha. with respect to the direction of movement of the periphery of the blade wheel.
Centrifugal pumps are used widely for the transfer of liquid materials and mixtures. Their pumping effect is created by the rotation of a blade wheel in a fixed casing of the pump. The blade wheel subjects the material to be pumped to a centrifugal effect by rotational movement so that, when the material reaches a discharge opening, it is discharged into it under the influence of the centrifugal force and the motion of the blade ends. Such pumps are disclosed, e.g., in DE patent publication 2,525,316 and FI patent 53,747.
A problem with pumps known from the prior art is the pulse-like pressure variation occurring in their discharge conduits, which is disadvantageous under certain operating conditions. In particular, when the pump is used as a feed pump for fibre suspension in the conduit system associated with the head box of a paper machine or the like, the pressure variations cause wave-like variations in the forming paper or cardboard web, thus deteriorating the quality. In an attempt to decrease the pulse, the radially outermost ends of the blades of the blade wheel of a pump have been made oblique in the circumferential direction of the blade wheel, but this has not eliminated the pulse disturbances.